Field of the Invention
The invention lies in the field of conveying two-dimensional, flexible objects, in particular printed products. The invention relates to a device for separating such objects from the lower side of a stack consisting of these objects and for conveying the separated objects away from the stack. The device comprises a stack space with a support region and support means supporting the stack from below in the support region, wherein the support means comprise at least one support roller arrangement of at least one support roller. Moreover, the device comprises at least one separating member for separating the objects from the lower side of the stack.
Moreover, the invention also relates to a method for separating individual, two-dimensional, flexible objects from the lower side of a stack of such objects and for conveying the separated objects away from the stack by way of a device according to the invention.
Description of Related Art
Such devices are known from the state of the art. Thus for example EP 1 226 083 B1 describes different embodiments of devices for separating individually printed products from the lower side of a printed product stack.
According to a first embodiment according to FIGS. 1 to 5, the stack on the one hand is supported over part of the surface on a stationary rest table and on the other hand on a movably arranged support disk pair. The rest table and the support disk pair form a horizontal rest surface. The support disks are rotatingly mounted about a vertical axis. The support disk pairing forms a release recess which in a release position below the stack forms an opening for the suction members and for bending away and pulling off the printed products. The release recess is periodically led through below the stack by way of the rotation of the support disks.
The rotating support disks on the stack lower side however produce a surface friction, i.e. they drag along the lower side of the stack. This procedure can led to a damaging of the lowermost product and generally to disturbances in the process procedure, such as e.g. an uncontrolled displacement of the printed products in the stack.
According to a second embodiment according to FIGS. 7 to 9, the device comprises a carrier wheel which is arranged below the stack and which rotates about an essentially horizontal axis. In each case, pairs of a sucker and a gripper assigned to the sucker are arranged on the periphery of the carrier wheel. Moreover, the device comprises a support means in the form of a roller carpet which on the one hand supports the stack from below and on the other hand comprises at least one removal opening, through which the respective lowermost printed product is gripped by a sucker, and can be bent against the gripper assigned to the sucker and transferred to this gripper, for separation from the stack. The roller carpet comprises a plurality of rollers which are mounted in a freely rotatable manner, are aligned parallel to one another and horizontally, and are moved along a revolving (which is to say circulatory) path in a revolving device. The rollers thereby are moved through below the stack in a manner directed essentially equally with the suckers and grippers.
A device is described in WO 2008/000099 A1, which serves the same purpose. Here too, a roller carpet is present, wherein the rollers of the roller carpet are fastened on a roller wheel which for example revolves on the same axis as the as the carrier wheel. The rollers run along a non-circular revolving path, along which the distance between the rollers is varied. The rollers are moreover articulately coupled on the roller wheel by way of levers, in a manner such that the levers are pivotable parallel to the rotation plane of the roller wheel. An unambiguous revolving or revolving path of the rollers and an unambiguous and always constant movement course of the rollers along this revolving path are defined by a roller guidance which controls the movement of the rollers along the revolving path.
EP 1 254 855 B1 likewise shows a roller carpet, with which the rollers are fastened on a roller wheel. In order to open the roller carpet in a certain region, the rollers are tilted away and specifically about a tilt axis which runs essentially radially or secantially to the roller wheel. A cam control is provided for pivoting the rollers. A wheel rolling on a cam moves the rollers via a lever mechanism with several levers.
EP 2 128 055 A2 likewise describes a device for separating printed products from a lower side of a printed product stack and for conveying away the separated printed products. The device comprises a stack space with a support region, in which the stack is supported to the bottom. Moreover, the device likewise comprises a revolving roller carpet with a plurality of rollers which are freely rotatable about their longitudinal axis and are moved through the support region and thereby support the stack to the bottom. The device moreover comprises revolving sucker and gripper pairings for separating the objects from the lower side of the stack and for the transport-away of these. The rollers in the support region are moved past below the stack in a manner directed equally with the suckers and grippers. The rollers of the roller carpet are coupled onto a roller wheel. The coupling according to this embodiment is designed such that the rollers with their longitudinal axis are pivotable relative to the roller wheel.
CH 637 087 describes a device for separating printed products from the lower side of a printed products stack and for conveying away the separated printed products. A support means in the form of a roller grate with a plurality of rollers is arranged below the stack. The rollers of the roller grate are likewise moved in a revolving device along a revolving path, wherein the revolving path runs through the support region of the stack.
CH 598 106 likewise describes a device for separating printed products from the lower side of a printed product stack and for conveying away the separated printed products. Here too, the support means for supporting the stack comprise rollers which are moved in a revolving manner and which are led through the support region of the stack rest.
Common to the publications mentioned above is the fact that the rollers of the support means are led in a revolving manner in a revolving device and in this manner are moved through the support region of the stack rest. According to particular embodiments of the publication cited above, the rollers of the roller carpet are additionally pivotable with their longitudinal axis.
The described devices have the disadvantage that these have comparatively large dimensions and accordingly assume much space on account of the roller carpets or roller grates, which are guided in a revolving manner. If moreover the devices comprise pivotably guided support rollers, then these have even greater dimensions.
However, for certain applications it can be advantageous or even necessary for the device to have a compact and thus space-saving construction manner. This object however can hardly be achieved with a circulatorily (revolvingly) guided support roller arrangement.